$%#@!!@# Out of H4831sc and the 6.5-06 is shooting

JustC

Ran the load ladder/OCW again thursday eve at 200yds this time around with the 6.5-06AI and 140gr a-max's. Went up in .3gr increments again from 49.6gr to 51.7gr. All ladders were shot 1 charge at a time in ascending order at 4 different targets containing 2 bulls per target ( 8 individual aiming points) Thus I fired 8 loads at 8 different targets, then allowed the barrel to cool, then fired another ladder ect until all 5 ladders had been fired.

I had previously fired the ladder as groups of like charges rather than in ascending order at differing targets. After revisiting the theories, I chose to shoot them in the "round robin" method which spreads the human error more evenly across the groupings. I was able to determine much more definitively that between 49.6-50.2gr is a sweet spot and again at 51.7gr another sweet spot shows up. Eliminating horizintle error due to cheek weld in only several groups is roughly as follows

the first 3 charges only consist of 4 rnds each due to the bore fouling in after the first 3-4rnds was evident by POI shift.

49.6gr .505" for 3 shots 1 misfire (first one in this 1000)
49.9gr .814" for 4 shots
50.2gr .757" for 4 shots (vertical grouping?)
50.5gr ~1.250" for 5 shots (1 slight flyer?)
50.8gr not worth measuring prob ~2-2.5"
51.1gr back down a bit to ~1.5"
51.4gr back out to ~2"
51.7gr .625" for 4 shots and 1 flyer I can only claim as my fault?

I will say I am quite happy with this rig so far. The A-max is definitely acceptable to this tube, next on to the Lapua 139gr Scenar and 140gr berger.

so now I have a solid lead on 2 charge ranges to work with and I can't get any 4831SC at the local shop for 2-3 weeks[:(!][:(!][:(!] FIGURES!! oh well, maybe the gunsmith has some I can grab[:D]

Anyone run a side by side test against regular H4831???

why chase the game when the bullet can get em from here?....
Got Balistics?

nononsense

Justin,

Are you chronographing these as you go along?

Do you have any Re-22 or better yet, some Re-25?

I'm not trying to tell you what to do but...

My calculations show you at about 85% load density with the 51.7 gr. load.

My notes indicate significantly higher loading density than what you're working with right now. My AMAX loads started at 55 gr. and went up from there.

Just a thought.

Best.

JustC

nononsense, what powder were you using in yours? I ran to 57gr of RL22 previously and got 3208fps avg for 5 shots[:0] which told me it was wayyy too high. The pockets were gone as well. My reamer I think was set originally for the 120gr pills but in comparing them, I am not losing much case cap at all. Were you running RL25 at 55gr+ or were you using the RL22?

I switched from rl22 to 4831sc because it has been so accurate in my 280AI as well as the RL22. I gave the slight group size edge to the SC but the velocity with very close accuracy to the RL22. I also had some H1000 doing very well but powder fouling was heavy.

any advice on this one for RL22 slightly short throated? I didn't have time for the chrono during the week, so I ran the ladder and will run it higher (no pressure signs yet) from 51.7gr on up. I hope to have time enough to chrono the ladder this week.

Thanks

why chase the game when the bullet can get em from here?....
Got Balistics?

nononsense

Justin,

The idea that you had a short throat ran through my mind while I was reading this earlier.

I had a couple of things that were slightly different from your set up. I was using RWS 7x64 Brenneke brass which is superb and a bit heavier in the web. My reamer is cut with a 0.060" parallel leade just in front of the chamber. The helps curtail rapid pressure increase, essentially spreading the curve out a bit. But it does not contribute to the degredation of the boattail by plasma.

I was using Re-25 simply because when I step down in neck diameter and barrel volume (cu. in.) the pressure generally rises to the point where the next slower powder fits right in. The 280AI loaded with a 162 AMAX can use the Re-22 in a nearly full or full case without hitting the ceiling on the pressure curve. But when I step down to the 6.5-06AI, I start with the Re-25 and work up without the rapid increase in pressures from the reduced neck diameter and bore volume. Slightly reduced case capacity has less effect on pressure than the reduced neck size and bore volume. Necking the same size case down from the .280 to the 6.5 is like reducing the nozzle on a fire hose, the pressure increases, sometimes substantially, so you need a slower powder. Besides, as much as I like Re-22, I've had some problems with pressure depending on the lot#. It has been a little inconsistant.

H-1000 needs to be full (slightly compressed) in order to burn completely and cleanly in the 6.5-06AI.

If you're going to run the Re-22 in the short throat chamber, my guess would be that 55 grains is going to be the top end with the 140 AMAX or similar bullets. Between you, me and the hole in the wall, take a look at the Norma 130 gr. Diamond bullet with this throat set up. Running at normal pressures, you can save about 20" of drop at 1,000 yds when compared to the 140 gr. AMAX.

Best.

JustC

nononsense,..WOW 20" (2moa) at 1000yds with a LIGHTER bullet. That interests me greatly. What about the 130gr makes it that much higher in the trajectory being a reduced weight/length?

OK, I'll grab the RL25 off the shelf and run some charges. With my slightly shorter throat, where would you start in the load range? Also, where would be a good starting point with the H1000? Thanks much for the help with this new one.

I think I stopped at 57gr H1000 with no pressure, just thought with the fouling I would be better served to jump to the faster powders. I did not try the 100% load or a compressed load so that may still work out. What is it about a compressed load that cleans up that powder burn?

Thanks

why chase the game when the bullet can get em from here?....
Got Balistics?

nononsense

Justin,

The difference is that both the 140 AMAX and the 130 Norma have the same BC while the Norma is a bit shorter as well (more case capacity). The difference can be modified by ordering them with moly for those that believe in that use, also. I don't use moly. The numbers work out to be ~195" drop with the 130's and ~215" with the 140's with a 300 yard Zero. I know what you mean, I was shocked when I first started working with these things. But they are hard to get...

My COL is running 3.400" with the 140 AMAX so I would guess that you should be able to get up in the area of 60 grains(?) of H-1000 and still be in the near upper range of pressure. Not knowing your COL, go slow. The addition of pressure to the H-1000 makes it burn cleaner. More of it burns in the case and in the first part of the barrel as opposed to some of it remaining unburned at lower pressures.

With the Re-25, I would start at 54.0 just to be very sure and work up. The short chamber probably has you up in the lands to start so the pressure will be higher than if you were starting off the lands.

Lots of folks poo-poo this older style case ('06) as not being very accurate but with this 6.5 chambering, I see it as being very accurate and useful in the longer range shoots. I've backed down from the BooBoo and the 6.5-284 and I'm working with cases in the lesser capacity ranges and some are even fairly old designs. It doesn't matter in the long run, it's all fun!

Keep in touch.

JustC

Thanks for the data NN, I'll run a few more ladders "hopefully" one eve this week. I know this will be a rough description, but if you can imagine the base of the 140gr a-max being just under the shoulder/nk junction when at .000", in your experience, how short is that throat and would I gain a lot of benefit from lengthening it for a bit more powder or will the 2950-3050fps range in the 06ai be obtainable with a harmonic she likes as is? I can chase the throat in this one if nothing else.

I am also quite excited about my "older" design 6.5x55AI. The forming is done and RL22 with the a-max is first up, then scenars once I get powder volume ideas. What do you think of those new Norma 130gr VLD's? They look nice anyway. These maybe what I should try? I am guessing the 123gr scenars are too light?

Thanks

why chase the game when the bullet can get em from here?....
Got Balistics?

nononsense

Justin,

I wouldn't bother trying to lengthen the throat based on your description. The gain is bound to be minimal. Besides, you're in the perfect position to chase the throat as it sits right now. The powder gain would be very small.

The hotshots are telling all of us that the accuracy node stretches from about 2875 fps to 3050 fps. depending on barrel length and bullet selected. Now, if I was using a 6.5x284 and one of the 140 class bullets, this will leave a significant air space in the case. Not conducive for small ES numbers and consistancy shot to shot. So I would think that a smaller, less capacious case would be better suited. I've got a couple underway using the 6.5x55 Swede case and the 6.5x57 Mauser case to see if they can cut it in the accuracy and consistancy tests.

I'm not fond of the shape and length of the 140 class bullets but I do like the 130 Norma and I think that it will be the rising star for 600 to 1,000 yard shooting. Match it up with the slightly smaller cases and voila! a competitive combination.

I think that the 123 Scenars are a bit too light for what we're 'aiming' for. I've used them for 600 yard shoots on a 250 Savage case necked up for 6.5 bullets. They also work good in the .260 Rem. at moderate ranges also.

Best.

JustC

what about the shape of the 130gr class attracts you more to them than the 140gr pills? Slightly less bearing surface? shorter tail?

why chase the game when the bullet can get em from here?....
Got Balistics?

nononsense

Justin,

I think it's just the overall proportions of the 130 that gets my attention, especially considering the performance of the 130's when compared to the 140's. A smaller, more efficient case and a lighter bullet with a better design is always more appealing.

Best.

JustC

I may have to try and find some of those new Norma 130vld's then and try em out. Now, where would you suggest I try to find the 130gr norma diamond pills?

Thanks

why chase the game when the bullet can get em from here?....
Got Balistics?

nononsense

Justin,

Check your e-mail!

Best.